1. Field of Invention
This invention relates to methods and systems that measure the edge step and edge form of a belt.
2. Description of Related Art
Electrophotography, a method of copying or printing documents, is performed by exposing a light image representation of a desired original image onto a substantially uniformly charged photoreceptor, such as a belt. In response to that light image, the photoreceptor discharges to create a latent image of the desired image on the photoreceptor""s surface. Developing material, or toner, is then deposited onto the latent image to form a developed image. The developed image is then transferred to a final substrate, such as paper. The surface of the photoreceptor is then cleaned of residual developing material and recharged in preparation for the production of another image.
If the photoreceptor is an endless belt, the belt may be produced by aligning the two opposite edges of a planar sheet of photoreceptor material and then sealing together the aligned edges. The sealed area is called the seam.
As shown in FIG. 1, seams may be produced containing a step that is a discontinuous, or uneven, change in the belt edge profile. That is, the two edges of the belt to be sealed together may not be perfectly aligned due to, for example, waviness of the planar sheet. This edge step and the underlying waviness in edge form, if greater than a given acceptable value, could increase undesired registration offsets between color separation images in a developed multi-color image formed during a print run.
Registration offsets in a developed image are undesirable because, when the developed image is transferred to a final substrate, the final transferred image will include the registration offsets. That is, each different color separation image will be slightly misregistered, or offset, relative to the other color separation images and/or the receiving substrate. These registration offsets, even if only a few mils or tens of microns, are well within the visual acuity of the human eye.
Thus, the quality of the resulting image suffers greatly even for small steps and small amounts of waviness in the edge forms of the belt that are greater than the acceptable values. Without learning the edge step and edge form of the belt, the degree of registration between the color separation images cannot approach the level of quality necessary for good image production. Complex, independent control systems are employed to ensure good belt production.
This invention provides systems and methods for determining the edge step and edge form of a belt.
This invention separately provides at least one sensor on a test belt that is capable of providing belt edge information for producing subsequent belts.
This invention separately provides a belt edge determination controller for a testing device that uses the determined edge step and edge form of the test belt to reduce or eliminate the edge steps and waviness in edge forms on subsequently produced belts.
This invention separately provides systems and methods that determine edge information of a test belt along a belt moving direction during a test run to adjust the production data to remove or reduce the edge steps and waviness in edge forms during production.
The systems and methods of this invention separately provide sensors which provide feedback signals indicating the edge step and edge form of the test belt during a test run.
The systems and methods of this invention separately provide a controller that determines the differences between sensor feedback values to obtain belt edge data and compares the belt edge data to acceptable values, and to initialize the production data as the acceptable values to reduce or eliminate the step and waviness in edge form of during production of subsequent belts.
Various exemplary embodiments of the systems of this invention include a testing device that includes sensors mounted at one side of the belt module. The sensor signals are sent to a belt edge determination controller to determine the edge step and edge form of the test belt. Then, the belt edge determination controller determines whether a determined edge step and edge form data are appropriate for subsequent production.
In accordance with the systems and methods of this invention, problems in registration during a print run, such as misalignment, are reduced or eliminated.
These and other features and advantages of the systems and methods of this invention are described in or are apparent from the following detailed description o exemplary embodiments of the invention.